Microminiature relay for transistor circuits



3,106,624 MICROMINIATURE RELAY FOR TRANSISTOR CIRCUITS 19, 1961 Oct. 8,1963 c. N. cHALLAcoMBE ETAL 2 Sheets-Sheet l Filed Dec.

INVENTORS, CARL N. CHALLACOMBE BY%Qf; 2A.R|EckMAN ATTORNEYY.

Oct. 8, 1963 c. N. cHALLAcoMBE ETAL 3,106,624

MICROMINIATURE RELAY FOR TRANSISTOR CIRCUITS Filed Dec. 19, 1961 2Sheets-Sheet 2l INVENTORS. CARL N. CHALLACOMBE .K BY @GER A.R|E KMAN MMMATTORNEY United States Patent O 3,106,624 MECRMENIATWE RELAY FRTRANSHSTUR CIRCUETS Carl N. Chaliacomhe and Roger A. Rieclnnan, Elgin,Ill.,

assignors to the United States of America as represented by theSecretary 'of the Army Filed Dec. 19, 1961, Ser. No. 166,676 4. Claims.(Cl. 20u-97) The present invention relates to hermetically sealedmicrominiature relays in the sensitivity range of 500 microwatts to 1.0milliwatt for use in transistor circuits.

The function of relays in many applications is the control of acomparatively large amount of power with a small amount of power. Whenthe power available to operate the relay becomes very small (on theorder of a milliwatt or less) it is not sutcient to operate relaycontacts in a conventional manner.

Recourse has been made in these low operating power situations tosensitive polarized relays and meter movement relays to accomplish theswitching operations. However, polarized and meter type relays areundesirable for Various reasons. Polarized relays require a volume offour to tive times that required by the relay of the instant invention.In addition, the polarized aspect was unwanted. The major drawbacks ofmeter type relays are the lack of current handling ability in thecontacts, the large size due to the magnet volume needed, and poor shockand vibration resistance. When the above mentioned relays are used,sacrifices must be made in size, ruggedness, and versatility to achievethe goal of controlling a large amount of power with a small amount ofpower.

Where only a low operating power is available for actuating the relaycontacts, the current carrying ability of the contacts is limited,especially in the conventional button or blade type contacts.Considerable pressure on the contacts is essential to handle the amountof power for which the relay of this invention was designed. Because therelay operating power is insufcient to operate the contacts in aconventional manner, a mechanical source of energy is supplied withinthe relay of this invention in the form of a mainspring. The release ofthis energy is controlled through an escapement which may be operated atvery low levels of power. The stored energy is used to operate thecontacts which switch higher levels of power.

An object of this invention is to provide a relay which will switchpowers on the order of 20 to 3G watts with relay operating powers of lto Smilliwatts while retaining the size, shock and Vibration resistance,and nonpolarized aspects of certain crystal can size relays.

Another object of this invention is to provide a new and novel relay.

Still `another object .is to provide a novel relay having shock andvibration resistance.

A further object of this invention is to provide a relay which occupiesa relatively small volume and yet is capable of switching comparativelyhigh currents.

A still further object of this invention is to provide a relay whichutilizes a mechanical source of energy to operate the relay contacts.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from the following descriptionand drawings wherein:

FIGURE l is a front View of the relay,

FIGURE 2 is a side View ofthe relay,

FIGURE 3 is a detailed view of the escapement mechanism ofthe relay,

FIGURE 4 is a detailed View of the actuator mechanism and contacts, and

3,105,624 Patented Oct. 8, 1963 FIGURE 5 is a detailed View which showsthe various connections which are made to the lead out terminals.

Referring to FIGURES l and 2, there is shown a microminiature relaywhich is hermetically sealed within an outer can Titi. Can 38 is omittedfrom FIGURE 2 in order to simplify the drawings. An inner can 37separates the coil structure from the remainder of the relay. in orderto obtain the desired length of coil and yet keep the overall size ofthe relay small, it is necessary to use two coils 73 and '74. The coreis made of four pieces. A U-shaped piece 5 is insertedy through thecoils from the top and pieces 6 and 7 are inserted from the oppositeends of coils 73 and 74, respectively. The core pieces overlapthroughout the length of the coils thus providing a long, large area,gap inside the coils. A better condition is thus achieved than could beobtained by a joint outside the coil. This type of core constructionallows the inner can 37 to be soldered to a center plate ttl and to thecores 6 and 7 where they leave the can. The fourth core piece 8 issecured to core piece '7' by core screws 24. Two insulating hermeticseals 71 are placed in plate itl inside the area covered by can 37 tosupport coil terminals 32. Two conductive leads 7? connect coils 73 and74 to the ends of terminals 32 which extend inside can 37. A conductivelead oil connects coils '73 and 74 in series. Coils 73 and 74 are woundupon insulating coil tubes 1li, while an insulating coil form end 9 ispositioned at the end of each coil. ber 5 to center plate 4t).

The energy needed to operate the two common relay contacts 43 is storedin the form of a wound spring (not shown) which is located within abarrel and cover 2. The barrel, housing the mainspring, revolves aboutan arbor 3 which is secured to the center plate 40. The mainspring isattached to the arbor and the barrel.

Rotation of the barrel due to the wound mainspring is coupled through anamplifying gear train to an escapement. When the electromagnetic circuitis energized the escapement is unlocked and energy is available tooperate the contacts.

The first gear '72 of the train is actually an integral part of thebarrel 2 and it drives a pinion 31 which is mounted on a stallU 3). Agear 13 which is also mounted on statt 3@ drives a pinion 29 causinggear 12 to drive pinion 2n which in turn causes gear llfto drive pinion27. Gears 12 and 11 are with pinions 29 and 28 respectively.

The escapement meclianisnrcan be more clearly seen in FIGURE 3. Theescapement wheel 35 is mounted on a shaft along with pinion 27 so thatit turns in the direction shown along with pinion 27. The armature 1,which is mounted on a staff 26, has two sapphire escapement pins 18 and18a mounted thereon which are adapted to engage the escapement wheelteeth. Pin 18 is generally referred to as the locking pin and lila theholding pin. In FIGURE l the armature 1 is shown in the nonenergizedcondition of the relay, while in FIGURE 3 the relay is in its energizedcondition. Armature stop 25, mounted on a post ZAM, keeps the armaturein proximity to core piece 8 when the relay is not energized. As therelay becomes deenergized the armature return spring Si), which ismounted on a post S1, returns the armature to the position shown inFIGURE l. A stop 23 limits the travel of the return spring. The gaplength between armature 1 and core piece 6 varies when the armaturepivots, being greatest when the armature is in the released positionwhile the coils are deenergized. To prevent, as much as possible, anyincrease in the total of the armature gaps in the magnetic circuit, asandwich-type gap arrangement is used between armature 1 and core piece8 to improve iiux transfer at this point.

A core rivet `2:2 secures a tab on core memixedly mounted on shafts yaroaeaa To improve vibration resistance of the relay the angle on theface of the escapement wheel teeth is such that the escapernent wheelmust back up or reverse-rotate against the mainspring torque as thelocking pin l is withdrawn.

The actuator and switching mechanism is best seen in FIGURE 4 while theswitch itself is shown in FiG- URE 5. The actuator wheel 36 is mountedon the same shaft as escapement wheel 35 and is provided with anundulating rim 60. The actuator arm le is mounted to the actuator shaft43 which is a sapphire rod. Two sapphire rods 46, which are attached toarm 4,4, ride on either side of rim 60 to provide a cam follower actionthat actuates the common switch contacts 4S. With this type of cam andfollower the actuator arm is restrained in all positions. Four iixedcontacts 47 andthe two common contacts form a double-pole, double-throwswitch. A iiexible conducting lead d2 connects each of the commoncontacts 4S to header terminals 65 and 67. Each of the fixed contacts 47is connected to a respective header terminal 62, 63, 68, or 69. Theremaining header terminals 64 and 66 are connected to coil terminals 32by two conductive leads 75. Header terminals 62 to 69 project through aninsulating header 1d.

Two supporting plates 39 and il are secured to header lll, while thecenter plate il is secured to the supporting plates by spacing posts 20,20a, and 2l. Jewels l5, le, 17, and 49, mounted in the various plates,provide bearings for the gear, armature, and actuator shafts or staffs.

The operation ofthe relay is as follows:

The escapernent wheel tends to rotate in the direction shown by thearrow in FIGURE 3 since it is coupled to the mainspring through the geartrain. The armature is normally in the position shown in FIGURE 1 due tothe action of the return spring, and therefore locking pin 18 preventsrotation of the escapement wheel. When the electromagnetic circuit ofthe relay is energized, the armature is rotated one half tooth space tothe position shown in FiGURE 3, and holding pin ida prevents rotation ofthe escapement wheel. A rotation of one half tooth space occurs again asthe electromagnetic circuit is Cle-energized. As the escapement wheelrotates, the actuator wheel also rotates since the two are on the sameshaft. Movement of the undulating rim of the actuator wheel causes theactuator arm to move as the two rods 46 follow the undulations of rim60. Since the common contacts 48 of the double-pole, doublethrow switchare connected to the actuator shaft d3, the reciprocating movement ofthe actuator arm is imparted thereto. Thus as the electromagneticcircuit is energized, the common contacts are switched to one set ofixed contacts 47, and as the electromagnetic circuit is de-energized,the common contacts are switched back to the other set of fixedcontacts.

By this construction and manner of operation a relay of very small sizeis achieved, yet it is rugged and reliable, and is capable ofcontrolling relatively large currents with low input power. lt iscapable of many thousands of cycles of operation, tested models havingachieved upward of 250,000 switching operations per winding.

What We claim is:

l. In an electromagnetic relay having a pair of contacts for controllingan external circuit, a source of stored energy, an escapement wheelhaving a plurality of teeth around the periphery thereof, saidescapement wheel being coupled to said energy source, an electromagnetpositioned adjacent said escapement wheel and having a tlat U-shapedcore having two arms joined by a cross-piece and a movable armature,said armature being pivoted in ovcrlappnig relation and closely adjacentto one of the arms of said core so that the gap formed thereby is smalland relatively fixed at all times, the armature and the remaining corearm forming a working gap, said armature being provided with a lockingpin which engages one of said teeth when said electromagnet iscie-energized, and a holding pin which engages one of said teeth whensaid electromagnet is energized, means connected to said locking pin forreturning said armature baclt to its initial position when saidelectromagnet is de-energized, and actuator means connected to saidescapernent wheel for operating said contacts by the energy releasedthrough said escapement wheel.

2. A relay as set forth in claim l wherein the faces of each escapernentwheel tooth form an angle with a line extending from the center of thewheel to said face such that said wheel must reverse-rotate when saidelectromagnet is energized, thereby giving resistance to vibration tosaid relay.

3. A relay as set forth in claim l wherein said actuator means includesan actuator wheel having an undulated rim, said actuator wheel beingmounted on a shaft with said escapement wheel so that both wheels rotatetogether; an actuator arm having two follower rods mounted thereon, oneof said rods being situated on each side of said rim; said contactsbeing connected to said arm.

4. An electromagnetic relay comprising: a mainspring, an escapementwheel having a plurality of teeth around the periphery thereof, a geartrain coupling said mainspring to said escapement wheel, an actuatorwheel having an undulated rim, a shaft, said escapement wheel and saidactuator wheel being ixedly mounted upon said shaft, an actuator armhaving two follower rods mounted thereon, one of said rods beingsituated on each side of said rim, a switch having a movable contact,said movable contact being connected to said actuator arm, anelectromagnet having a U-shaped core comprising two arms joined by across-piece, a coil situated on each arm of the core, an armaturepivotably mounted adjacent the arms of the core so that one portionthereof is brought into contact with one of the core arms when saidelectromagnet is energized, a return spring for returning said armatureto an initial position when said electromagnet is cle-energized, saidarmature being provided with a locking pin which engages one of saidteeth of said escapement wheel when said electromagnet is de-energized,and a holding pin which engages one of said escapement Wheel teeth whensaid electromagnet is energized, said switch being operated when saidelectromagnet is energized and being reset for repeated operation whensaid electromagnet is de-energized.

References Cited in the tile of this patent UNITED STATES PATENTS1,191,205 McCormick Iluly 18, 1916 2,710,323 Andrews June 7, 19552,906,838 Deighton Sept. 29, 1959 FOREIGN PATENTS 350,582 Great BritainJune 18, 1931

1. IN AN ELECTROMAGNETIC RELAY HAVING A PAIR OF CONTACTS FOR CONTROLLINGAN EXTERNAL CICRUIT, A SOURCE OF STORED ENERGY, AN ESCAPEMENT WHEELHAVING A PLURALITY OF TEETH AROUND THE PERIPHERY THEREOF, SAIDESCAPEMENT WHEEL BEING COUPLED TO SAID ENERGY SOURCE, AN ELECTROMAGNETPOSITIONED ADJACENT SAID ESCAPEMENT WHEEL AND HAVING A FLAT U-SHAPEDCORE HAVING TWO ARMS JOINED BY A CORSS-PIECE AND A MOVABLE ARMATURE,SAID ARMATURE BEING PIVOTED IN OVERLAPPING RELATION AND CLOSELY ADJACENTTO ONE OF THE ARMS OF SAID CORE SO THAT THE GAP FORMED THEREBY IS SMALLAND RELATIVELY FIXED AT ALL TIMES, THE ARMATURE AND THE REMAINING COREARM FORMING A WORKING GAP, SAID ARMATURE BEING PROVIDED WITH A LOCKINGPIN WHICH ENGAGES ONE